Is there a site which offers an interactive F# shell? - f#

Is there a site like try ruby that allows one to experiment in an F# interactive shell? I'd like to try a few commands without installing Visual Studio or Mono.

There is also now tryfs.net.

Not yet that I know of. (This is something the F# team would love to do if/when we can find the free time to put it together.)
(Note that you don't need VS or Mono - you can just have .Net and then install the F# CTP and just get the runtime, command-line compiler, and fsi.exe, and use that. But it would be nicer if there were a no-install web-site-visit try-it thingy.)

You can use codepad.org for experiments with OCaml. The core of F# and OCaml is similar, just remember not to use light version of syntax, advanced F# features and .net libraries :)

ideone.com now supports F# ! Here are some samples.
It's not really a REPL, but rather an online compiler.

Related

How do I implement an F# Read Eval Print Loop (REPL)?

I would like to add an F# REPL to my application for live debugging purposes. I am looking at the source code for fsi.exe (F# Interactive) and there is a ton of stuff going on that looks like it pokes around with F# compiler internals. I cannot get this same code to compile in the context of our application because of this.
Is there a nice simple example of implementing an F# REPL somewhere? I would have hoped for this to be fairly easy.
The short answer is that F# (unfortunatelly) doesn't currently provide any API for hosting F# Interactive in your applications. There are a lot of people asking for this - see for example this SO question.
There are essentially two things you could do about that:
You can modify the open-source release and compile fsi.exe as some DLL library that would provide the API you need. This isn't simple task - F# Interactive is tightly bound with the compiler (it compiles code you enter on the fly), but it should be doable to encapsulate the types implementing REPL into some type you could call (But you cannot just take some file out of it - you need to compile entire F# to get this working).
You can run fsi.exe as a separate process as Visual Studio does and send commands to it using standard input/output. You can get some more flexibility by loading your library when fsi.exe starts. The library could use .NET Remoting to connect back to your application and expose some data.
Unfortunatelly, these two options are probably the only things you can do at the moment.
EDIT I was thinking that I already answered this question somewhere (perhaps in email), but couldn't
find it! Thanks to Mauricio who found the exact duplicate (even with my duplicate answer... Doh!)
I've written a series of blog posts about using the open source F# interactive executable inside and WPF application.
The code base is available on github - https://github.com/oriches/Simple.Wpf.FSharp.Repl
The series of blog posts are:
http://awkwardcoder.blogspot.co.uk/2013/12/simple-f-repl-in-wpf-part-1.html
http://awkwardcoder.blogspot.co.uk/2013/12/simple-f-repl-in-wpf-part-2.html
http://awkwardcoder.blogspot.co.uk/2013/12/simple-f-repl-in-wpf-part-3.html
The final post is to follow soon.

Embedding F# interactive

Is there an easy way to embed F# interactive (fsi.exe) terminal into an application? More generally, is the code for fsi.exe available to make tweaks to, etc?
The code for fsi.exe ships along with the CTP (check the license, but eventually I think we eventually want to make it MS-PL, if it is not already).
There is not a particularly easy way to embed it.

What tools are built using themselves? [closed]

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I am curious about what tools are used to build the next version of themselves.
For example, Delphi has long claimed that "Delphi is written in Delphi".
I assume Visual Studio is written using Visual Studio.
What are some other examples of tools that written in themselves?
Interestingly, the VB.NET & C# compilers themselves are written in unmanaged C++ (leading to the C++ team's T-Shirt: "My compiler compiled yours"). The C# team hopes to have a fully managed-C# hosted C# compiler for VS2010.
Bjarne Stroustrup mentioned in The Design and Evolution of C++ that the first C++ compiler was written in C++.
I've just noticed this is also a question in his FAQ:
The first C++ compiler (Cfront) was
written in C++. To build that, I first
used C to write a "C with
Classes"-to-C preprocessor. "C with
Classes" was a C dialect that became
the immediate ancestor to C++. That
preprocessor translated "C with
Classes" constructs (such as classes
and constructors) into C. It was a
traditional preprocessor that didn't
understand all of the language, left
most of the type checking for the C
compiler to do, and translated
individual constructs without complete
knowledge. I then wrote the first
version of Cfront in "C with Classes".
This is off-topic, but strictly speaking, it is an example of a tool which builds itself.
The reprap - an open-source 3d prototyping machine, which recently gave 'birth' to "its first complete working replicated copy".
I love this kind of stuff.
Generically speaking, C compilers are usually written in C... *nix kernels are compiled on *nix, etc.
Also, there's the pypy project which provides a Python interpreter written in Python.
When gcc (the Gnu C compiler http://gcc.gnu.org/) was not available widely, you had to compile it from source, compiling stage1 compiler, then compile stage2 with stage1, till you have your final compiler. I assume it must be the same today.
Here is another example: Mono's C# compiler is self hosting - i.e. it's written in C# and used to compile itself.
Dog fooding refers to the more general practice of a company using its own product internally, especially during its development.
Lots of folks like to look at how Lisp can be implemented in Lisp.
Squeak is a Smalltalk-80 implementation written in itself.
even its virtual machine is written entirely in Smalltalk making it easy to debug, analyze, and change.
Sun's Java compiler has long been written in Java. However, recent work is writing a JIT compiler in Java as well. This is the JVM component that converts Java byte code to native processor instructions.
We use to develop using RealBasic. The IDE is written in itself, or so I've been lead to believe.
ghc, the Haskell compiler, is mostly written in Haskell.
tcc is another self-hosting C compiler for x86 and ARM. Its claim to fame is being, well, tiny (100k or so for preprocessor, compiler, assembler, and linker).
I would assume that pretty much any tool that's part of the typical development process would be involved in its own development, to whatever extent possible. This includes:
certain programming languages, especially compiled ones
IDEs
text editors
version control systems
bug trackers
build systems
If you're on a team building one of these tools, and you're not developing it for a specific niche that doesn't apply to your team, I don't know why you wouldn't use it to build itself. Having developers be users of the product is one of the best ways to find possible improvements.
For the AmigaOS there was a third party Basic interpreter (don't remember the name) for which you could later buy a compiler. The compiler was delivered as source, so you had to use the interpreter to run the compiler to compile itself...
To cite Kent Beck:
...it may seem a bit like performing brain surgery on yourself.
Visual Studio and Team Foundation Server build themselves. It's called dogfooding, a term which if not originating in Microsoft, it certainly likes
Oracle Application Express is a web application development tool that is built in itself.
Eclipse IDE is generally built and developed using Eclipse IDE.
It is fairly typical to have a languages compiler written in its own language. This is called self-hosting or bootstrapping.
Maven2 is built using Maven2.
Ok, it's not built (i.e. written) using itself, as it is a tool to build (i.e. compile) project, but it is using its own code to compile...
I was amazed with JSLint
In short it has been described as Javascript "compiler" using javascript.
I am building an IDE-based code generator, and I am using it to build itself. If fact, as Stroustrup did, I am first building a valid generator model and using a pre-processor to build the final C++ code to compile. Once I have a good working version of the IDE, I'll start using it to build further versions of itself.
It's like giving a new dimension to the meaning of "recursive programming"!
AFAIK does the OpenJDK build itself first with the installed java and afterwards with itself.
Naturally the Jetbrains team uses its own IDE IntelliJ IDEA to develop this IDE.
I assume this is true for most IDE vendors.
As far as I know, when building EMACS from source, all of the ELISP code is bootstrapped. I found that quite noteworthy.
Not quite what you're asking for, but the entire development environment for Revolution http://www.runrev.com is built using Revolution itself, and the source (except for small parts that enforce the license) is completely exposed in source form. So if you don't like the way the dev environment is implemented, you can change it. Find a bug, fix it. You can also easily build additional development tools and integrate them.
Ada and Forth
I gave the Smalltalk-80 answer an uptick. Best, most elegant example I can think of. The question also reminds me of a slightly related problem that used to be popular: write a program that outputs itself. Not the same level of bootstrapping, but a fun little programming puzzle for your amusement. Maybe not possible in all languages?
The old Watcom C/C++ compiler was built using itself.
Kragen Sitaker's Ur-Scheme is a fine example of a small nontrivial compiler written in itself. That page links to several more good sources in that vein.

FxCop/StyleCop for Delphi?

Does anyone know of an equivalent to FxCop/StyleCop for Delphi? I would really like to get the automatic checking of style, etc. into Continuous Integration.
There's Pascal Analyzer from Peganza: http://www.peganza.com/products_pal.htm
I don't know how the features compare to FxCop, since I haven't really used either one.
The closest I've seen is CodeHealer from SOCK software. We use it, and we have integrated it into our FinalBuilder build. It differs from FxCop in one important way: It analyzes the source code, rather than the produced executable. It also doesn't check quite as much as FxCop does. But I think it is the best thing which is available in this category for Delphi.
Delphi 2009 support isn't there just yet, but they say they're working on it.
Delphi Code Analyzer is another one that is open source.
The DGrok project started with something like FxCop some years ago. The parser and analysis parts are still available, read more at "DGrok 0.8.1: multithreading, default options, GPL" - The parser is a .Net project but
DGrok is a set of tools for parsing
Delphi source code and telling you
stuff about it. Read more about it on
the DGrok project page.
There is a new Delphi plugin for Sonar, which uses a Delphi grammar to run automatic tests over the source code.
I've heard of something called Delforex but haven't used it myself (yet)
Delforex is great for actually formatting the code. It does not do much more than that though. (we have/do use it).
I would second the votes for either Pascal Analyzer or Code Healer.
Vaccano
Doesn't Delphi output .net compatible IL code? I haven't used it in an age but I thought newer versions output .net assemblies.
If so then I would have thought FXcop would work and you could always add some of your own custom rules to it. Stylecop would not work but you could at least get FXCop running.

Are there any support tools like coderush or resharper for F#?

Are there any support tools like coderush or resharper for F#?
Preview version of FSharpRefactor released in Visual Studio Gallery.
http://visualstudiogallery.msdn.microsoft.com/339cbae9-911d-4f99-9033-3c3564676f45
http://www.youtube.com/watch?v=T6-YjUULNCA/
F# Refactor open source project on CodePlex (Apache license).
Take a look at the open-source Visual F# Power Tools project. They've got a rename refactoring, some code generation stuff (eg. record stub generation), graying out of unused declarations, as well as some other things. They're moving pretty fast at the moment, with lots of new features getting added all the time.
There's an effort to support F# in ReSharper via an external plug-in (itself written in F#). You can find preliminary info here.
FSharpRefactor 0.1 (Preview version) Released on the Visual Studio Gallery.
http://visualstudiogallery.msdn.microsoft.com/339cbae9-911d-4f99-9033-3c3564676f45?SRC=Home
Not yet, as far as I know. I was also looking for something similar to no success. I suspect as soon as F# hits VS2010 as its integral part, or even a bit earlier, such tools will eventually emerge.
As far as ReSharper is concerned, you may want to drop JetBrains a quick email, it would be interesting to know whether these guys have any plans regarding F#.
Since the push in f# is towards light mode the reformatting possible is likely to be both limited, and hard to implement.
Normally reformatting takes the structural information and uses that to create the textual position. In the case of #light the textual position (of indenting at least) is the structure. As such any reformatting would be at best to sort inter symbol spacing, hardly onerous to do yourself.
I would therefore not expect a commercial product for it at least until the 'proper' integration with the IDE (I do not consider the current CTP proper in this regard since several outstanding bugs with it exist which will not be fixed in 2008)
CodeRush is working in F# editor. At least some code assistance and code templates. But code templates are not defined yet (you have to create your own).

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